128 



THE ENTOMOLOGIST. 



Fig. 33.— Orphnepbila. 

 .7 e 



1i^ 2* ^ /// 



Fig. 24.— Dixa. 



In Sciara the nearness of the cubital bone to the costa is 

 apparent, and there is a transition through some intermediate 

 forms between this genus and Cecidomyia, where the bones 

 mostly disappear. In Bibio the arrangement of the bones is 

 quite changed, and the new pattern is continued in the two 

 following genera, Plecia and Penthetria (figs. 13, 14), where 

 the cubital is forked. Penthetria differs chiefly from Plecia 

 in the shortness of the radial, and in the junction of the first 

 branch of the cubital with the costa, and not with the radial. 

 In Scatopse (fig. 15), which is the type of the second division 

 of the Bibionidae, the cubital is again near to the costa, and 

 is joined by a transverse bone to the first branch of the pra3- 

 brachial, and there is an undulating subaxillary. In Aspistes 

 (fig. 16) the structure is much more simple, and A. H. Haliday 

 remarks that its analogy to that of Scatopse is very doubtful. 

 In the Chironomidae (figs. 17, 18) there is another plan in the 

 formation of the bones: neither the cubital nor the praebrachial 

 is forked, and the anal extends to a greater distance from 

 the base of the wing ; the hovering flight and the great swarms 

 of some kinds of this family are well known. In Culex (fig. 

 19) another change occurs: the longitudinal bones are more 

 numerous, and the passage from it by Phlebotoraus (= Haj- 

 masson, fig. 20) to the little moth-like flies (figs. 21, 22), whose 

 abundance and feeble flight are well known in this country. 

 I have placed Orphnephila (fig. 23) with the Chironomidae, 

 and Dixa (fig. 24) next to the Tipulidse, as the formation of 

 the wings agrees generally with that of Limnobia and of the 

 neighbouriug genera. 



Francis Walker. 



